Train control



Patented Jan. 7, 1930 PATENT; *OFFEICE NED C. L. BROWN, OF SCOTTSVILLE, NEW YORK, ASSIGNOR 'TO'GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK TRAIN CONTROL Application filed October 15,1923. Serial No.668,622.

This invention relates-to automatic train control systemsof the lnductive type, and

more particularly to systems inwhich alternat-ing'current is employed for transmitting control influences fromthe trackway to the railway vehicle.

In applying automatictrain control apparatus to a train, it is'found necessary to transmit control influences from the trackway to the moving train so that it may be controlled in accordance with traflic conditions ahead. On account of the speed at which trains move along the trackway at times, weather conditions and clearances, it is difficult to transmit such control influences by physically contacting devices on the train and along the trackway; and it is desirable to transmit control influences inductively through an intervening air gap to obviate this difficulty. A comparatively simple expedient for producing an influence on a moving train consists in inducing current in a coil or closed circuit carried by the train by electro-magnetic induction. In order toinduce such a current in the closed circuit on the train, a changeof magnetic flux is necessary, and since it is important that control influences be transmitted at extremely low speeds as well as at high speeds, it is desirable to produce such change of flux in some way other than by the movement of the vehicle alone.

In certain types of train control systems, the usual engineers brake valve is actuated automatically to, apply the brakes of the train; and in order to assure the operation of this brake valve, regardless of the failure of the source of electrical energy or of circuits, the engineers valve is preferably constructed to assume its active position by the release of a certain force, rather than the application of such a force.

iVith the above and other important considerations in mind, it is proposed in accordance with the present invention to provide inductive influence communicating means which includes an inert trackway device requiring no trackway energy source, and suitable cooperating car-carried devices including an alternating current source of energy,

whereby the cooperationof these car-carried and trackway devices may cause the transmission of a control influence from the trackway to the vehicle under predetermined conditions of the trackway device regardless of the speed of the train and to provide suitable pneumatically operated means for moving the usual engineers brake valve to the service brake applying position in response to the release of pressure from a cylinder.

More specifically, it is proposed to provide influence communicating means in which the car-carried element has a primary winding energized by alternating current, and a secondary winding connected to a control relay, both of these .circuits being tuned to resonance at the frequency of the alternating current source; and the trackway device is an inert mass of iron which disturbs the resonant constants of the circuits mentioned whereby the control relay is deenergized, the inert trackWa-y device being provided with a coiland associated parts so constructed that underclear traific conditions the constants of the circuits are not disturbed It is also 1 proposed to provide suitable influence'communicating means for restoring the control relay to normal which includes a trackway transformer portion adapted to cooperate with the car-carried primary Winding heretofore mentioned, and another trackway transformer portion electrically connected thereto underclear traffic conditions ahead for transmitting a control influence to a carcarried transformer portion. This method of transmitting restoring control influences is conveniently called the transformer scheme, and is especially well adapted for transmitting restoring influences, since the failure of a circuit prevents the transmission of such influence and makes the system function on the correct. principle, namely, failure on the sideof safety. For automatically applying the brakes, it is proposed to provide a piston in a suitable cylinder which is mechanically connected to the usual engineers brake valve and is urged by main reservoir pressure of the usual air-brake system to the brake applying position, another and larger piston being provided which, under normaltraflic conditions, opposes the force exerted on the bodiment of the present invention, and which.

illustrates the manner in which the carcarried and trackway devices are adapted to cooperate and transmit control. influences distinctivein character.

Tmclcway apparatus In the particular embodiment of the invention illustrated, one track of a double track railway system has been shown, the normal direction of traflic being from left to right, as indicated by'the arrow, The reference character 1 designates the rails of the track which are divided by insulating joints 2 into blocks. Since the various blocks are the same, the block I and the adjacent ends of the blocks H andJ only have been shown; and for convenience like parts of each block have been assigned like reference characters having distinctive exponents. Each block is provided at the exit end with the usual track battery 3 supplying energy through the usual track circuit to a track relay 4: located at the entrance end.

The traincontrol system embodying the present invention is preferably used in conjunction with the' usual" wayside signals of either the color light, position light or semaphore signal type; and for convenience semaphore signals Z have been illustrated conventionally without showing their well-known control circuits and apparatus, the signal to the entrance of each block being preferably cont-rolled by the track relay of said block and a track relay of the block next in advance, preferably indicating clear when both of these blocks are unoccupied, caution when the second block in advance only is occupied, and indicating danger when the block next in advance is occupied, all in a manner well understood by those skilled in the art.

Near the entrance end of each block, or rather braking distance in the rear of the exit end ofeach block, is a track element T adapted to initiate a suitable car-carried control relay if the next block in advance is occupied. This track element T of the block I consists of a U-shaped core of magnetic material 5, having upstandinglegs terminating in enlarged pole pieces 6 and provided with a coil 7 on the back yoke thereof. This coil is normally connected in a closed deenergized circuit of low resistance by the front contact 8 of-a line relay 9, which is energized through 'way secondary and trackway primary transformer portions, respectively, for transmitting restoring control influences to the vehicle. These trackway transformer portions TS and TP are substantially the same, and each comprises a U-shaped core 11 having upstanding legs terminating in enlarged pole pieces 12, the back yoke of the core 11 being surrounded by a winding 13, The windings 13 of the trackway transformer portions TS and TP located in the block I are included in a deencrgized circuit passing through the front contact 14 of the track relay P, so that said windings are connected in series when the block J next in advance is unoccupied.

Oar-carried apparatus Influence communicating and control de- -cices.On the locomotive or other railway vehicle is provided a car-carried element L, comprising a core 15 of general inverted U-shape and constructed of magnetic material. The legs of this core 15 terminate in pole pieces 16, adapted to cooperate with the pole pieces 6 and 12 respectively of the track elements T and TS as the'railway vehicle moves along the trackway. On the legs of the core 15 of the car element L are primary coils P, which are connected in series through a suit-able condenser 17 across the terminals of a suitable alternating current generator AC. The condenser 17 is preferably of such capacity that the energizing circuit for the pri- -mary coils P is in resonance when the car element L is moving between control points in a block, that is, the circuit for energizing the primary coils P is resonated, so that a maximum amount of current flow and resulting magneto-niotive-force is present in the car element L while said element is not near an active track element.

On the back yoke of the core 15 of this car element L is a secondary coil S, which is connected in multiple with a condenser 18, having a condensive reactance equal to the inductive reactance of the secondary coil S for the frequency of the alternating current source AC, so that a maximum potential exists across the condenser 18 when the car element L is moving along the trackway between control points. Across the condenser 18 is connected a suitable control relay OR, in series with a suitable rectifying device A, so that the alternating current derived from the secondary winding S may be rectified and applied to the control relay OR to maintain it .in its energized condition. r In the particular embodiment of the invention illustrated, this rectifying device A is of the three-element thermionic or vacuum tube type,in-which-the grid 20 and the plate 21 have been connected together, and in which 'thefilament 22 is heated by current flowing from-a suitable filament battery 23. The circuit forenergizing the control-relayGR by unidirectional current, rectified by the rectifying device A, may be traced as follows:-

Beginningat the'secondary coil S,-wires 24 of this device, through'wire 30 'back'to'the secondary winding S -of the car element L.

is should be noted that this circuit includes a front contact 26 of the control-relay CR, thus constituting a stick circuit for this relay, and that momentary deenergization of the control relay GR causes it to remain deenergized until otherwiserestored, because the energizing circuit just tracedis broken *at the front contact of this relay. Since the primary windings P are energized by a circuit resonated to the frequency of the alternating current source AC, and since the second ary coil Sis resonated by the condenser 18 to a potential resonance for this same frequency, a maximum potential is applied across the rectifying device A and control relay CR under normal conditions of the apparatus.

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The control relay GR is constructed to act very quickly in response to a small change of current, it being of the tractive armature type in which avery light armature is used so that the inertia of moving parts only slightly retards its operation. The armature of this relay is preferably pivotally supported about its center of mass so as to make it balanced and not subject to jars and vibration, but responsive only to the flow of current through its winding. For various reasons, it is preferable to operate relays of this type by uni-directional current and the rectifying device A is employed to furnish such current. For instance, alternating current tends to cause chattering whereas pulsating direct current tends to smooth itself out into a substantially continuous direct current. Also, the flow of alternating current is much reduced by reason of the inductive reactance whereas inductive reactance does not resist the flow of uni-directional current.

If now the car element L passes over an active track element, such as the track element T when in an active condition, the resonant condition of both the primary and secondary circuits just mentioned is disturbed so that the total amount of alternating current flux passing through the secondary coil S of the car element is reduced, and the potential across the condenser 18 for each unit change of flux is reduced by reason of this non-resonant condition of the circuit includingthe primary coils.

This considerably smaller 1 potential induced in the circuit including the secondary coil S in itself results in a proportional reduction in the current rectified --fiowing through the control relay GR, buta still I further reduction in the potential across the condenser 18, and consequently across the relay- OR, is produced by reasonof' the nonresonant condition of the circuit including the secondary coil-Sand.thecondenser 18.

' Since the inductive reactance of the coil S is duced on the control relay CR, when the car element passes over an active track element, is equalto the effect produced by reason of the-non-resonant condition of the primary winding, modified by the effect produced by the non-resonant condition of the secondary coil and its associated condenser, so that the ultimate effect produced is equal to the product of the separate effects produced as a re sult of bringing the primary and the secondary circuit out of resonance. It is this multiplied effect that causes a very pronounced change in the current flowing in the control relay CR and since this relay is of the quick acting, unidirectional current, tractive armature-typein which the armature is extremely light, a momentary reduction only of current in the control relay is necessaryto cause its operation. This reduction inthe energizing current for thecontrol relay CR causes it to open its front or stick contact 26, thereb maintaining deenergization of this relay y reason of complete interruptionof its energizingcircuit. i V

- In order to-again automatically restore the control relay OR, a suitable restoring or reset relay RE is provided. This reset relay ER .is at times energized in response to a control influence received by the car-carried transformer portion LS located to cooperate with the trackway transformer portion TP. This car-carried transformer portion LS consists of an inverted U-shaped core 35 terminating in enlarged pole pieces36, and having windings 37 provided on each of the legs of this core 35. These windings 37 are connected in series across the reset relay RR through a condenser 38. The condenser 38 preferably has acapacity so that the condensive reactance of this condenser is substantially equal to the sum of the inductive reactances of the car element LS and the reset relay RR for the frequency of the alternating current source AC, so that the restriction to the flow L has passed over a track element T in its active condition, thisarelay may again be restored by the momentarv energization of the reset relay RR as the train is about to pass tion TS, an alternatingcurrent is induced in the winding 13 of this element TS, thereby causing alternating current to flow in the winding 13 of theother trackway transformer portion TP, so that an alternating current magneto-motive-force is set up in the core 11 of the transformer portion TP. Since the car-carried transformer portion LS is in inductive relation with the transformer portion TP at the instant the car element L passes over the transformer portion TS, a similar alternating current flux is set up inthe carcarried transformer portion LS, thereby inducing a voltage in the windings 37 which, by reason of the resonant condition of the circuit including the reset relay RR, causes sufiicient current to flow to energize this reset relay RR. This reset relay BB is preferably slow dropping,-so that its front contact 39 is closedfor a considerable period of time.

' As the car-carried elements L and LS recede from the trackway transformer-portions TS and TP; suificient voltage is again impressed upon the condenser l8to energize the control relay CR'through the following circuit :Beginning at the secondary winding S'of the car element Lywires 24 and 40, front contact 39 of the reset relay-RR, wires 41 and 28, winding of the control relay CR, wire 29, through the rectifying device A, wire 30 back to the secondary'winding S of the car element L. The momentary completion of this circuit causes the control relay OR to assume its energized position, thereby again completing the stick circuit heretofore traced and restoring the control relay OR to its normal condition.

Speed restrictingapparatus.-Althougl1 the control relay GR may be used to control the train in a caution block in any suitable manner, it is proposed toernploy this control relay CR for controlling the operation of a suitable speed control apparatus or speed restricting device; and a speed restricting device of the cyclic type which provides a restriction in the speed in accordance with the movement of the train along the trackway has been conventionally illustrated. The apparatus or device conventionally shown comprises a centrifugal speed-responsive device or governor Gr, including a shaft 45 journaled in projecting bosses 46 and 47 and driven by the wheels and axle of the railway vehicle in any suitable manner, as by transmission gearing. To the shaft 45 is pinned a collar 48 having projecting ears to which are pivotally secured links 49. The

free ends of the links 49 are pivotally con nected' to similar links 5.0, having their other Lends connected to ears projecting from a sleeve 51 slidably mounted on the shaft 45. At the junction point of the links 45 and are providedweights 52, corresponding to the centrifugal weights of the well knownv furc'ated end of a floating. lever 54, the other .end of this floating lever 54 being provided with a roller 55 riding on the edge of a cam K. A hook 56 is pivotally secured to the floating lever 54 at an intermediate point, and is urged downwardly by a spring 57, having its free end anchored to a pin 58. The hook 56 terminates in a piece of insulation 59 adapted to engage a spring contact finger 60, if the hook 56 assumes a predetermined elevated position. i The cam K, on which the roller 55 hereto- -fore mentioned rides, normally assumes the position with this'roller 55 in its lowermost position as shown, thereby allowing the gov- 'einor G- to rotate at a comparatively high speed before the insulation 59 raises the contact 60. r-This cam K is firmly secured to a shaft 61 pivoted in journals 62 and 63. The shaft 61 is provided with a worm gear 64, having a mutilated portion 65. To the shaft 61 is pinned a collar 66, having a projecting arm 67 urged in a predetermined position by the coil spring 68, and having its other end secured to an anchoring pin 69. It is thus seen that the spring 68 acts to urge the cam -K" to its normal position as shown in the drawing.

i To thegovernor shaft 45 is pinned a bevel gear 75, which meshes with a bevel gear 76 pinned to a shaft 77 pivotally secured by the journal'78. A shaft 79 is operatively connected to the shaft77 by a universal joint 80, so that this shaft may be rotated by the shaft 77 regardless of the exact alignment of these two shafts. he free end of the shaft '79 fits loosely in a sleeve 81 fastened to the core 82 of a cam starting magnet CS, having a winding 83. free end thereof is provided" a worm 84 adapted to engage the worm wheel 64when V the cam starting magnetCS is deenergized. Under normalclear traffic conditions of the carcarried apparatus, that is, when the control relay CR is energized, the cam starting magnet CS is energized through a circuit including the battery 85 and the front-contact 86'of the control relay CR, which may be readily traced in the drawing.

It will'be noted that deenergizati on of the control relay CR causes the cam starting On the shaft 79 and near the magnetv CS to assume its deenergized position, thereby mechanically coupling the governorshaft 4:5driven by-the wheels of the vehicleto the canrK, As the train-moves along the trackway, the cam K is gradually rotated in one direction or the other, depend ing upon whetherithe train is moving pilotior tenderfirst, thereby gradually moving the rollerupwardly, thus causing the insulation 59'to move toward the contactGO. It is thus seen that the speed whichthe-vehicle may assume, without causing the insulation 59 to open the contact 60, must begradually reduced as the roller- 55 assumesihigher posi tionsin response to the. movement of the cam K driven by the worm8 l,

hen the vehicle has moved a predeter mined distance along the trackway after the cam starting magnet CS-hasbeen deenergized, theworm SLreachesthe mutilated portion of the worm wheel 64;.so-that no further rotation of the worm wheel 64 takes place. regardless of: the continued rotation of the worm 8 1. This construction is provided so thatthe ultimate speed limit enforced by the particular cam K will continue until the cam starting magnet CS is xagain energized.

Brake applying mecham'svm-In the embodiment of the invention illustrated, suitable means for causing an automatic brake application have been provided, which is made effective when the contact is opened as a result of excessive speed, that-is, actual speed manifested bythe governor Gas compared with the permissive speed set up by the position of the cam K, as heretofore described. As shown,'the brake applying apparatus includes an electro-pneun'iatic valve EPV having a winding which is energized by a circuit including the contact60 and a suitable source of energy such as a battery 91. This electro pneum'atic valve EPV comprises a chamber having partitions 92 and 93 dividing the chamber into compartments 9 1, 95 and 96. These partitions 92 and 93- are provided with valve seats adapted to accommodate valves 97 and 98 secured to the valve stem 99, having its upper'end guided inthe plug 100 and havingits lower end secured to an armature 102 disposed in the magnetic shell 103 of this electro-pneumatic valve EPV, the shell 103 being closed at its lower end by a non-magnctic cap 104. On the valve stem 99 is a collar 108, between which and the partition 93 is interposed a compression coil spring 109. i

The electro-pneumatic valve EPV just de-' scribed is adapted to control a brake valve actuator attached to the valve casing of the' usual engineers brake valve as illustrated. The particular engineers brake valve shown is of the engine and tender or E; T. type, and is provided with a valve and seat having the necessary ports to provide arelease, running, holding, lap, service and emergency position as shown by the, various notches. This engineers brake valve E includes a valve stem 110,: to which is securedthe usual brake valve-handle 111 and-a projectingarm 112. Directly below the handle .111 and loose onthe valve stem is a pinion 113 zmeshingwith a rack- 114, which has its ends secured to a large piston 115 and-a small piston 116, respectively. These pistons 115xand 116 are provided with the usualrings. or packings and; lit: in cylinders 117 andi118 which-are integral "with and form part of a housing 119 secured to the top of the usuali engineers brake valve casing. The pinion 113 has therein an upstanding pin 120, which is adapted to engage the arm 112 projecting-from the valve stem 110 after a predetermined arc of movement of the pinion1l3 from its normal position. Thus, if the pinion 113 is rotated in a counter cloclnvise direction as shown, a certain amount of lost motion will: take place before the pin 120 engages the arm 112 to operate the valve handle and cause an automatic application of the brakes. This lostmotion is provided so that the engineer may move 'the handle 111 to the release position under normal conditions of the brake valve actuating mechanism without causing en-i gagement of the arm 112 and the pin 120.

The small cylinder 118 is provided with a pipe 124 directly and permanently connected to main reservoir or other source of air pre sure, so that air pressure of a predetermined amount is always present in this cylinder 118. The upper compartment 94 of theEPV is connected to main reservoir pressure by the pipe 125; the lower compartment 96 is in communication with atmospheric pressure through the port 126; and the middle fcompartment is connected'to the large cylinder 11'; of the brake valve actuator by the pipe 12 1 With the electro-pneumatic valve EPV in its normal energized condition, main reservoir pressure may pass fromthe compartment 94 into the compartment 95and through the pipe 127 into the large cylinder 117. Since the pressures in the cylinders 117 and 118 are the same, and since the cylinder 117 is larger than the cylinder 118, the force exerted on the piston 1 15 predominates over the force exerted on the piston 116, thereby maintaining the rack 114 in its extreme righthand position, as shown. 7

If now the circult for energizing the wind-' I ing 90 of the EPV is interrupted'because the speed limitas set up bythe cam K has been exceeded, the valve. 97 is closed and the valve 98" is o pened, so that the compartment 95' is connected to atmosphere through the compartment 96, thus releasing the pressure from the cylinder 117 and causing the rack'll l to move toward the left by reason of main reservoir pressure in the cylinder 118. This differential action of thepistons 11'5'and 116 is deemcd'to be extremely reliable,in that the' force necessary to operate the engineers valve to the brake applying position is derived by main reservoir pressure which must neces- Operation Let us assume that the car-carried apparatus illustrated in the drawing is in its normal or clear traffic condition as shown, and that the car or locomotive is moving in the block H, while the blockJ is occupied. As the train proceeds through the block H, the car-carried elements L and LS come into communicating relation with thetrackway transformer portions TS and TP without producing any action on the car outside of the momentary energization of the reset relay RR. As the train moves into the block I, which is a caution block because the block J is occupied by another train, acertain restriction in the movement of the train through this block is required.

. With the block J occupied by another train as just" assumed, the track relay 4 is deenergized, thus deenergizing the line relay 9 and opening the circuit for the track element T. As the car element L passes by the track element T, the momentary cooperation of the core 5 with the core 15 through a small intervening air gap causes the inductive reactance of the primarywinding P and the secondary winding S of the car element L to change momentarily. This momentary change in the inductive reactance of the primary and secondary windings disturbs the resonant condition of the exciting circuit for the primary coil, and also the energizing circuit for the control relay CR, so that the maximum amount of flux passing through the car element L as well as the potential impressed across the condenser 18 for each unit change of this magnetic flux is appreciably reduced,

thereby efl'ectingan enormous reduction in the flow of current through the control relay CR, causing it to drop its front contact 26 and break its energizing stick circuit. Vith the control relay OR deenergized, the opening of its front contact 86 causes deenergization of the cam-starting magnet CS and allows the worm 84 to operatively engage the worm wheel 64:.

' i As the train proceeds through the block I,

the gradual rotation of the cam K, by reason of the engagement of the Worm 84 with the worm wheel 64, causes a radually restricting speed limit to be set up y thechanging position of the roller of the floatinglever 54C. The shape of the cam K is preferably such that the permissive speed thus set up assures stopping of the train before reaching the end of a block. Since the braking'distance of a particular train in different blocks varies with the grade and the like, and since this distance varies for different trains on account of the length of the train, conditions of the brake shoes, loading of the various cars, and the like, it is considered desirable to cut the cam K to restrict the train to a certain arbitrary value found suitable for the various conditions encountered in practice.

The cam K is preferably so cut that a minimum speed limit of, say, 15 miles per hour, is established when it reaches its ultimate position, so that the train may continue to run at this low speed limit after passing the end of a caution block.

Let us assume that the train has passed through the block I and has reduced its speed below the permissive speed set up by the cam K, and that said another train has moved entirely out of the block J before the train in question reaches the trackway transformer portions TS and TP. With the block J again unoccupied and the track relay 4 energized, the front contact 14 is closed and the coils 13 are again in a closed circuit. As the car elements L and LS. simultaneously come into cooperation with the trackway transformer portions TS and TP, an alternating current is induced in the trackway circuit including the coils 13 by reason of the alternating fluxemanating from the pole pieces 16 of the car element L. This current flowing in the coils 13 of the trackway transformer portion TP sets up an alternating magnetic flux in the car-carried transformer portion LS, thereby inducing a current'in the resonated circuit of the reset relay RR, causing it to pick up its front contact 39.

As these car elements L and LS recede from the trackway transformer portions TS and TP, a resonated condition of circuits'including. the primary coil P and the secondary coil S again take place; and since the reset relay HR is slow dropping, the control relay GR is again picked up through the pick-up circuit including the front contact 39 of the reset relay RR. After this control relay GR is once picked up, the pick-up circuit heretofore traced is again completed, thus permanently maintaining this control relay CR energized.

Had the block J still been occupied by said another train when the car in question reached the trackway transformer portions TS and TP, no resetting control influence would have been transmitted, because the circuit connecting the coils 13 would have been open under this condition, and the train in question would have been compelled to pass through the block J at the minimum speed restriction heretofore mentioned with the line relay 9. Asthe car element L passes.

over the track element T, a current is set up in the coil 7 of thistrack element '1" which opposes the passage of flux from the car'element L through the core of the track element T to a large extent, so that the inductive reactance of the primary coil P and the secondary coil S of the car element L is only slightly changed, whereby the resonant condition of the circuits including these coils is not appreciably disturbed and the current energizing the control relay GR is not sufliciently reduced to cause this relay to be deenergized. In other words, the closure of'the coil? in a suitable circuit of low resistance, which may include either inductive or condensive reactance, causes this core 5 to lose its inherent inductive qualities, so that the self-induction of the car element L is not materially changed as it passes over this track element under. clear traffic conditions ahead. I V

Having thus shown and described one specific embodiment of the present invention, it is desired to be understood that the specific embodiment shown and described has been chosen for illustrative purposes, rather than to show the srope of this invention. For instance, the present invention may be used in connection with any type of speed restricting apparatus in which a certain initiating control is effected when entering caution territory, and a suitable-restoring control iseffected when entering a clear block; and it is desired to be understood that various-other changes and modifications maybe made to adapt the invention to the various railway systems encountered in practice without dea parting from the scope or the idea of means underlying the present invention.

, that is desired to be secured by Letters Patent of the United States, is

1. Influence communicating means for automatic train control systems comprising,'a car-carried core of magnetic material having a. primary and a secondary coilthereon, a source of alternating current on the car for energizing said primary coil, a condenser connected in series with said primary coil, a

condenser connected in multiple with said secondary coil, an electro-resp'onsive device connected in multiple with said last mentioned condenser, and tratficcontroll-ed means along the trackway for magnetically bridging said core under predetermined traflic conditions ahead.

2.. Influence communicating means forautomatic tram control systems comprising,- .a

car-carried core of magnetic material having a primary and a=secondary coil thereon, a source of alternating current of a predetermined frequency for energizing said primary coil, means for resonating the circuit for said primary coil to the frequency of said source, an electro responsive device connected to said secondary coil, means for resonating the circuit including said secondary coil'and said electro-responsive device to the frequency of said source, and trackway-means positioned in direct inductive relation to the car-carried core, for disturbing the resonant condition of said primary and secondary circuits when the car-carried core passes thereby.

3. Car-carried apparatus for automatic train control systems comprising; a car-carried speed restricting device of the type in which a cam is at times driven from the wheels of the vehicle which sets up gradually decreasing speed limits when so driven and which eifects an automatic brake application ifthe actual speed ofthe vehicle exceeds the permissive speed; means for initiating said speed restricting device including a resonated alternating current circuit including a control relay; and means for restoring said device including means for transmitting a control influence to a trackway circuit through an intervening air gap, and means to transmit a control influence from the trackway back to the car through another intervening air gap.

4. Car-carried apparatus for automatic train control systems comprising; a car-carried speed restricting device which sets up gradually decreasing speed limits when initiated and which causes an automatic brake application if the actual speed of the vehicle exceeds the permissive speed; means for initiating said speed restricting device including a resonated coil and a control relay; means for restoring said speed restricting device including a core of magnetic material having a winding thereon, a reset relay connected to said winding, and means for resonating the circuit including said reset relay'and said winding.

- 5. Car-carried apparatus for automatic train control systems comprising; a carcarried speed restricting device whichv sets up gradually decreasing speed limits when initiated and which causes an automatic brake application if the actual speed of the vehicle exceeds the permissive speed; means for initiating saidspeed restricting device comprising two resonated circuits, one of which is directly connected to a source of alternating current of the frequency for which these circuits are resonated, and a control relay normally connected in a stick circuit; and means fluence receiving coil connected in the circuit with said reset relay, and means for resonating the circuit for said resetrelay to the frequency of said alternating current source.-

6. Influencecommunicating means for auomatic train control systems comprising two car-carried electrically insulated circuits resonated to a predetermined frequency, and a single element located at each of a plurality of control points along the trackway, positioned in direct inductive relation to said circuits, and controlled in accordance with traflic conditions ahead simultaneously directly affecting both of said circuits upon passage of the car-carried circuits by such control points and thereby simultaneously changing the resonant condition of both of said circuits.

7. Influence communicating means for antomatic train control systems of the intermittent inductive type comprising, a car-carried core having a primary coil and a secondary coil thereon, a source of alternating current for energizing said primary coil, a relay connected in series with said secondary coil in a circuit including a front contact of said relay, said relay being maintained energized by energy derived from said source through the inductive coupling including said core, means for resonating the circuit including said primary coil at the frequency of said source, means for resonating the circuit including said secondary coil and said relay at the frequency of said source, and traffic controlled trackway means which when-in its active stopping condition magnetically cooperates with both said primary and said secondary coil to disturb the resonant condition of both of said coils upon passage of said core by said trackway means, whereby the current flowing in said relay decreases to a value to allow said relay to assume its deenergized position and thereby interrupt the energizing circuit of said relay.

8. Influence communicating means for automatic train control systems, comprising the combination of a car-carried influence receiving element including a laminated core located so as to be in inductive relation with the trackway, a coil on said core, a control relay having a front contact, a circuit includ: ing said coil, the winding of said relay and said contact in series, a source of alternating current for energizing said circuit, means for resonating said coil at the frequency of said source, rectifying means in said circuit for allowing the flow of uni-directional current only through the winding of saidrelay, and of trackway means which when in its active condition-disturbs the resonant condition of said coil upon passage of said coil by said trackway means, whereby said relay is caused to assume its de-energized position when the car passes an active trackway device.

9. A train control system of the intermittent inductive type comprising vehicle carried apparatus including a core having a primary coiland a secondary coil thereon, a circuit for energizing said primary coil including'an alternating current source of supply,- a stick relay, a secondary circuit including the secondary winding, the winding and a front contact of said stick relay, means for resonating said primary circuit to a predetermined frequency, means for resonating said secondary circuit to the same frequency, and

trackway means for disturbing the resonant. condition of both of said circuits upon passage of the vehicle thereby, said trackway means including an iron core having a winding thereon which winding is open circuited under unfavorable traflic conditions.

10. The combination with a track and a vehicle moving thereon, of a brake system including an engineers valve having manual movement to extreme positions, and means located along the track and upon the vehicle for placing the engineers valve in an intermediate position and at the same time effecting a reduction of pressure in the brake system, said means being ineffective to place'said valve in any other position and including differential area piston mechanism constructed so that it is actuated if pressure is released therefrom and is restored to normal after such pressure is reapplied.

11. In inductive influence communicating apparatus for automatic train control systems of the intermittent inductive type, the combination with a vehicle carried core having a primary and a secondary Winding thereon, a primary circuit including the said primary winding and a source of alternating current, a secondary circuit including the secondary winding, a winding and a front contact of a stick relay, means for resonating said primary. circuit to a certain frequency, means for resonating said secondary circuit to the same frequency, and trackway means located in inductive relation with said core upon passage of the vehicle by said trackway means.

12. Gar-carried apparatus for automatic train control systems of the intermittent inductive type comprising, a core having a primary coil and a secondary coil thereon, another core having an inducing coil thereon, a stick relay having a front contact, a source of alternating current, a restoring relay, a

circuit for said primary coil including said v alternating current source and tuned to the frequency of said source, a circuit for said secondary coil including thewinding of said stick relay and its front contact in series also tuned to the frequency of said source,and a. circuit for said inducing coil including said restoring relay and also tuned to the fre- .rrmaasi ing said alternatingcurrent source and tuned to the frequency of said source, a circuit for said secondary coil including the Winding of.

said stick relay. and its front contact in series also tuned to the frequency of said source, a circuit for said inducing coil including said restoring relay and also tuned to the frequency of said source, and a pickup circuit for saidstick relay including a front contact of said restoring relay; of trackway apparatus including a track element consisting of an ienert magnetic body when in its active condition fordisturbing-the resonated condition of said primary and said secondary circuits nnder danger traific conditions, and means for .electro-magnetically coupling said primary coil to said inducing coil under clear traflic conditions. i

14. ,In a train control system of the inter-. mittent inductive type, the combinationwith car-carried apparatus including; a core having a primarycoiland a secondary-coil thereon, another core having an inducing coil thereon, .a stick relay having a front contact, a source of alternating current, .a restoring relay, a circuit for said primary coilincluding saidalternating current source and tuned to the frequency of said'sourcaacircuit for said secondary coil including the inding of said stick relay and its front contact in serics ,alsotuned tothe frequency of said source, a circuit for saidinducing coil includingsaid restoring relay and also tuned to the frequency of saidsource, and a pick-up circuit for said stick relay including a front contact of said restoring relay; of trackway apparatus including a track element consisting ofan inert magnetic :body when .in'its active condition for disturbing the resonated condition of said primary and said secondary circuits under danger traffic conditions, and other trackxvay means for inducinga current in said inducingcoil to pick-up restoring relay eiiective under clear traffic conditions.

15. Influence communicating meansfor automatic-train control systems comprising, a car-carried core ,ofmagnetic material having a primary and a secondary coil-thereon, a

source of alternating current of a predetermined frequency for energizing said primary,

coil, means for resonating thecircuit forsaid primaryicoilto thefrequency of saidisourc a stick electro-responsive device connected 'to said secondary coil, means for resonating the circuit including said secondary coil and said electro-responsive device to the same frequency, trackway means for disturbing the resonant condition of said primary and said secondary circuits When the car-carried core passes thereby, and thereby causing said electr c-responsive device tobe de-energized, and means for restoringsaid electro-responsiveidevice to normal. 7

1.6. Influence communicating means for automatic train control systems comprising, car-carried-core of magnetic material having a primary and a secondary coil thereon, a source of alternating current of a predetermined frequency for energizing said primary coil, means for resonating the-primary circuit including said primary coil to the "frequency of-said source, a stick electro-respom sive device connected to :said secondary coil, means for resonating the secondary circuit includingsaid secondary coiland said electroresponsive device to the same frequency, trackway means for disturbing the resonant conditioniof said primarylandsaid Secondary circuit-s when the car-carried core passes thereby and thereby causing said electro-responsi-ve .deviceto he deenergized, and vmeans controlled from the trackway through'an intervening air gap for restoringsaid electroresponsive device to normal. a

1,7. Influences communicating means for automatic train control systems comprising, a car-carried core of magnetic material having a primaryanda secondarycoil thereon, a source of alternating current of a predetermined frequency for energizing said primary coil, means for resonating the primary circuit including said primary coil tothe frequency of said source, a stick electro-responsive device connected 'to said secondary coil,

means for resonatingithe secondary circuit including said secondary coil and said electro-responsive device to the same frequency, trackway means for disturbing the resonant condition of said primaryand said secondary circuits when the car-carried core passes thereby and thereby causing said electro-responsive device zto -be .c'leenergized, and a :re-

storine rela havin a front contact which if soft iron core for simultaneously magnetical- 1y linking both of said circuits upon passage of a vehicle :by a control point, and thereby passage of the vehicle by simultaneously changing the resonant condition of both of said circuits to detune such circuits.

19. Influence communicating means for automatic train control systems comprising, a car-carried element of magnetic material having a primary and a secondary coil thereon, a source of alternating current on the car for energizing said primary coil, a condenser connected in series with said primary coil, a condenser connected with said secondary coil, said condensers tuning the circuits of the two coils for the frequencies of said current source, an eleetro-responsive device connected to the secondary coil and traffic controlled means along'the trackway for magnetically brid ing said element under predetermined trafiic conditions ahead to cause initiation of said electro-responsive device by detuning said circuits.

20. Influence communicating means for automatic train control systems comprising, car-carried inductively related primary and secondary coils, a source of alternating current of a predetermined frequency for energizing said primary coil, means for resonating the circuit for said primary coil to the frequency of said source, an electro-responsive device connected to said secondary coil,

' means for resonating the circuit including said secondary coil and said electro-responsive device to the frequency of said source, and trackway means for disturbing the resonant condition of said primary and secondary circuits when the car-carried coils pass thereby to thus detune said circuits and initiate said electro-responslve device. I

21. Influence communicating means for Y automatic train control systems comprising a car-carried magnetizable core, a primary and a secondary coil on said core, two electrically insulated circuits each including one'of said coils, a source of alternating current for energizing the circuit including the primary coil, said circuits being resonated to the frequency of said source, a relay in the other circuit normally energized by current derived from flux emitted by said primary coil, and means located along the trackway which under dangerous trafiic conditions ahead disturbs the resonant condition of said circuits by bridging the core when said core moves by said trackway means whereby to decrease the current n the secondary circuit so as to de-energize said relay.

22. Influence communicating means for automatic train control systems comprising, two car-carried coils located in inductive relation with the trackway, two electrically insulated circuits each including one of said coils, a relay connected in one of said circuits, a source of alternating current connected only in the other circuit, said circuits being resonated to the frequency of said source of alternating current, and means located at points along the trackway which under dangerous traflic conditions ahead simultaneously detunes both of said circuits by magnetically cooperating with said coils, the various constants being so selected that said relay will assume its de-energized position when the resonance of the two circuits is disturbed by reason of the co-operation of said car-carried coil and the means located along the trackway.

V 23. Influence communicating means for automatic train control systems of the intermittent inductive type comprising, a carcarried'primary coil and secondary coil, a source of alternating current for energizing said primary coil, a relay connected in series with said secondary coil in a circuit including a front contact of said relay, said relay being maintained energized by energy derived from said source through inductive coupling, means for resonating the circuit including said primary coil at the frequency of said source, means for resonating the circuit including said secondary coil and said relay at the frequency of said source, and trafl ic controlled trackway means which when in its active stopping condition magnetically cooperates with both said primary and said secondary coil to disturb the resonant con dition of both of said coils upon passage by said trackway means, whereby the current flowing in said relay decreases.

, 24. A traincontrol system of'the intermittent inductive type comprising vehicle car: ried apparatus including a primary coil and a secondary coil, a circuit for energizing said primary coil including an alternating current source of supply, a stick relay, a secondary circuit including, the secondary winding, the windingand a front contact of said stick relay, means for resonating said primary circuit toa predetermined fre-- quency, means for resonating said secondary circuit to the same frequency, and trackway means for disturbing the resonant condition of both of said circuits upon passage of the vehicle thereby, said trackway means including "an iron core having a winding thereon which winding is open circuited under unfavorable traflic conditions.

25. In inductive influence communicating apparatus for automatic train control systems of the intermittent inductive type, the combination with a'vehicle carried primary and secondary winding, a primary circuit including the said primary winding and a source of alternating current, a secondary circuit including the secondary winding and a winding of a stick relay, means for resonating said primary circuit to a certain frequency, means for resonating said secondary circuit to the same frequency, and trackway means located in inductive relation with said windings upon passage of the vehicle by said trackway-means, a i

26. Influence communicating means for automatic-train control systems comprising, a car-carried primary and secondary coil, a source of alternating current of a predetermined frequency for energizing said primary coil, means for resonating the circuit for said primary coil to the frequency of said source, a stick electro-responsive device connected to said secondary coil, means for resonating the circuit including said second ary coil and said electro-responsive device to the same frequency, trackway means for disturbing the resonant condition of said primary and said secondary circuits when the car-carried coils pass thereby, to thereby cause said electro-responsive device to be de energized, and means for restoring said electro-responsive device to normal.

27. The combination with a track and a vehicle moving thereon, of a brake system including an engineers valve having manual movement to extreme positions, and means located along the track and upon the vehicle for placing the engineers valve in an intermediate position and at the same time eflecting a reduction of pressure in the brake system, said means being ineffective to place said valve in any other position and including a differential piston normally having equal unit pressures on its two ends.

28. A combined manual and automatic brake applying device comprising; an engineers brake valve having a brake pipe charging position and a non-charging position; a member normally assuming a position permitting said brake valve to assume any of its positions in response to manual operation; and means for forcibly operating said member to cause said brake valve to be moved to a non-charging position consisting of differential area fluid pressure responsive means which responds to fluid pressure acting on the smaller area after fluid pressure is vented from the larger area and which means restores said member to normal when fluid pressure is reapplied to the large area, and an electrically operated valve controlled by suitable train control means for venting fluid pressure from the larger area when the brakes are to be automatically applied.

29. A combined manual and automatic brak e applying device comprising; an engineer s brake valve having a brake pipe charging position and a non-charging position; a member normally assuming a position permitting said brake valve to assume any of its positions; and means for forcibly operating said member to cause said brake valve to be moved to a non-charging position consisting of differential area fluid pressure responsive means, which respond to fluid pressure acting on the smaller area after fluid pressure is vented from the larger area and which means restores said member to normal when fluid pressure is reapplied to the larger area, and an electrically operated threeeway valve controlled by suitable train control means for normally applying fluid pressure to the larger area from a suitable fluid pressure source and for venting fluid pressure from said larger area when an automatic brake application is to'take place. 7

Q50. A "brake 'valve actuatorvfor operating an engineers brake valve from a normal brake pipe charging position to an abnormal non-chargingposition comprising, differential piston means including two pistons of diiferent areas' having fluid pressure derived from the same source normally acting thereon and acting in such a manner that the forces of the two pistons oppose each other and the force ofthe larger piston predominates and operates the actuatorto and retains theactuator in the normal position, and means for venting fluid-pressure from the larger piston to allow the force exerted upon the smaller piston to move the engineers brake valve to the nonwharging' position when the :engineers brake 'valveis to be auto matically operated.

31. In atraincontrol system, the-combination with anengineers brake valve having a brakep ipe charging position and anoncharging position, a member normallyassuming a position permitting said brake valve to assume any-of its positions in responseto manual operation, means for forcibly operating said member to cause said brake valve to be moved to a non-charging position consisting of differential area fluid pressure responsive means, the response of which is due to fluid pressure acting on the smaller area upon fluid pressure being vented from the larger area and which means re-- stores said member to normal when the source of fluid pressure is reapplied to said larger area; and a normally energized electro-pneumatic valve for normally supplying fluid pressure against the larger area and which if de-energized vents the fluid pressure from the said larger area.

32. Influence communicating means for automatic train control systems, comprising,

a car-carried magnetizable core terminating in two depending legs, a primary and a secondary coil on said core, two electrically insulated circuits each including one of said coils, a source of alternating current for en ergizing the circuit including the primary coil, each of said circuits being resonated to the frequency of said source, a relay in the other circuit normally energized by current caused by flux emitted by said primary coil and means located along the trackway which, under dangerous traflic conditions ahead, disturbs the resonant condition of said circuits by magnetically bridging said legs when said core moves past said trackway means, whereby to drop said relay.

33. In an inductive train control system,

a car-carried core having a primary and a secondary coil thereon, a circuit for the primary coil including an alternating current source, a circuit for the secondary coil including a translating device, means tuning each of said circuits to the frequency of said source, a track element in inductive relation to said core and consisting of an inert magnetic body for decreasing the magnetic reluctance of the circuit through the car-car-V rie'd core to thus detune the car circuits and initiate said translating device.

34. In an inductive train control system, a car-carried core having a primary and a secondary coil thereon, a circuit for the primary coil including an alternating current source, a circuit for the secondary coil including a translating device, means tuning each of said circuits to the frequency of said source, a track element in inductive relation to said core and consisting of an inert magnetic body for decreasing the magnetic reluctance of the circuit through the carcarried core to thus detune the car circuits and initiate said translating device, a choke coil on thetrack element, and traflic controlled means for opening and closing a low resistance circuit including the choke coil.

In testimony whereof I hereby aflix my signature.

NED C. L. BROWN. 

